Typestate crashes on this program

```
fn main() {
    let _a = 1, _b = 2, _c = 3;
    for d in [1] {
        {|x| x == 10 };
    }
}
```

The error is:

```
rt: b8e9:main:main:                   upcall fail 'Assertion i < v.nbits failed', src/lib/bitv.rs:75
rt: b8e9:main:                        domain main @0xa858148 root task failed
```
